Preparation of alkylaluminum halides



United States Patent 3,290 349 PREPARATION OF ALKYLALUMINUM HALIDES Allan J. Lundeen, Ponca City, Okla., and Donald M. Coyne, Prairie Village, Kans., assignors to Continental Oil Company, Ponca City, Okla., -a corporation of Oklahoma No Drawing. Filed May 31, 1963, Ser. No. 284,318

Claims. (Cl. 260-448) .of a trialkylaluminum. However, the alkoxides are ineffective in many applications in which the corresponding halide or dihalide can be used. Among such applications are use as a polymerization catalyst, use as an alkylation catalyst, reaction with acid halides, and use -in a low pressure growth reaction. Because of equilibrium and association considerations of organoaluminum compounds, prediction of a suitable method for preparing alkylaluminum chlorides is generally considered to be impossible on the basis of present knowledge of such systems.

It is an object of this invention to provide a process for preparing alkylaluminum halides. It is another object of the invention to provide a process for converting alkylalurninum alkoxides to alkylalurninum halides.

Other aspects, objects and the several advantages of this invention will become apparent upon study of this disclosure and the appended claims to the invention.

.According to the invention, there is provided a process for preparing an alkylaluminum chloride which comprises contacting a compound of the structural formula RR AIOR wherein R and R each comprises alkyl of at most 3 carbon atoms and R is selected from the group consisting of alkyl and cycloalkyl, with aluminum chloride, and recovering from the reaction mixture a compound selected from the group consisting of RR AICI,

RAlClg and R AlCl The reactions of this invention can be illustrated as fiollows:

sult in a mixed product of monoand dihalides. The.

usual ratio of starting materials is at least one equiva- ICC lent of chlorine per alkoxy group, and is preferably in the range of about 1:1 to about 9: 1.

Suitable di(lower alkyl)aluminum alkoxides include diethyl aluminum ethoxide,

di-n-propyl aluminum cyclopentanoxide,

di-i-propyl aluminum 4-ethylheptanoxide,

ethyl-n-propyl aluminum n-dodecanoxide,

ethyl-i-propyl aluminum Z-ethylcyclohexanoxide, n-pr-opyl-i-propyl aluminum i-pentoxide,

methylethyl aluminum n-butoxide,

dimethyl aluminum n-triacontanoxide, and methyl-n-propyl aluminum. 2,3-diamylcyclohexanoxide.

Neither pressure nor temperature are critical in the reactions, and we accordingly prefer to carry out the reaction at about room temperature and, as will be explained, at a pressure of about atmospheric or less, although pressures and temperatures above or below atmospheric are within the scope of the invention. The reaction proceeds rapidly, and is accordingly adapted to short contact time. Of the aluminum alkoxide starting materials of the invention, the lower alkoxides are liquid, and a preferred procedure of efiecting the reaction consists merely in dissolving anhydrous aluminum chloride in the alkoxide without solvent or diluent. However, the higher aluminum alkoxides are solid, and an inert solvent or diluent is in this instance desirable in order to eifect intimate contact of the reactants. Further, the reaction should be carried out in the presence of an inert atmosphere, such as nitrogen, argon, krypton or helium, in order to prevent decomposition of the reactants and products.

The reaction mixture is separated into the desired products as by distillation. In view of the thermal sensitivity of the products, separation is preferably effeeted at low pressure, e.g., at about 50 mm. Hg or lower. Removal of the halide product in this manner as overhead, with alkoxide product remaining behind as distillation residue, also has the advantage of shifting the reaction equilibrium in a forward direction.

The invention will now be further illustrated by the following specific examples.

Example 1 One hundred grams of diethylaluminum 2,2-dimethyll-pentoxide (B.P. C./7 mm. Hg) was mixed with 18 g. anhydrous aluminum chloride. The aluminum chloride dissolved with evolution of heat. Distillation of the reaction mixture yielded 18 g. of material boiling below diethylaluminum 2,2 dimethyl-l-pentoxide, which latter material was about 60% diethylaluminum chloride. Analysis showed:

Calculated for Calculated for diethylalumidiethylaluminum 2,2-di- Found num chloride methyl-1- pentoxide Aluminum, percent 22. 5 13.5 18.4 Chlorine, percent 29. 6 O 19. 8 Ethane evolved by hydrolysis, l./g 0.373 0. 224 0. 303

Example 2 Sixty-five grams of dimethylalu-minum n-butoxide are Having thus described the invention by providing specific examples thereof, it is to be understood that no undue limitations or restrictions are to be drawn by reason thereof and that many variations and modifications are within the scope of the invention.

What is claimed is:

1. A process for preparing an al kylaluminum chloride which comprises contacting a compound of the structural formula RR AlOR wherein R and R each comprises alkyl of at most 3 carbon atoms and R is selected from the group consisting of alkyl and cycloalkyl, with aluminum chloride, and recovering from the reaction mixture a compound selected from the group consisting of RR AICI, RAlCl and R A1Cl 2. The process of claim 1 wherein R and R are each ethyl, and wherein R contains between 2 and about 30 carbon atoms.

3. A process for preparing a dia-lkylaluminum chloride which comprises contacting a compound of the structural formula RR AIOR wherein R and R each comprises alkyl of at most 3 carbon atoms and R is selected from the group consisting of alkyl and cycloalkyl, with about an equimolar quantity of aluminum chloride, and separating from the neaction mixture a dialkylalutrninurn chloride of the structure RR AICI.

4. The process of claim 3 wherein R and R are each ethyl, and wherein R contains between 2 and about 30 carbon atoms.

5. The process of claim 4 wherein R is 2,2-dimethyln-amyl.

6. A process for preparing an alkylaluminum dichlo ride which comprises contacting a compound of the structural fonmula RR AlOR wherein R and R each comprises alkyl of at most 3 carbon atoms and R is selected from the group consisting of alkyl and cycloal'kyl, with about 2 moles aluminum chloride per mole of alkyl aluminum alkoxide, and separating from the reaction mixture alkylaluminum dichloride.

7. The process of claim 6 wherein R and R are each ethyl, and wherein R contains IbetWI1 2 and about 30 carbon atoms.

8. The process of claim 7 wherein R is 2,2-di-methyl-na-myl.

9. A process for preparing an alkylaluminum chloride and dichloroa-luminum alkoxide which comprises cont-actin-g a compound of the structural fiorrnula RR AlOR wherein R and R each comprises alkyl of at [most 3 carbon atoms and R is selected from the group consisting or" alkyl and cycloalkyl, with aluminum chloride, and subjecting the reaction mixture to low pressure distillation to recover as distillate at least one compound selected from the group consisting of RR AICI, RA1Cl and R AlCl and as residue a compound of the formula AICI OR.

10. The process of claim 9 wherein R and R are each ethyl, and wherein R contains between 2 and about 30 carbon atoms.

No references cited.

T-OBIAS E. LEVOW, Primary Examiner. 

1. A PROCESS FOR PREPARING AN ALKYLALUMINUM CHLORIDE WHICH COMPRISES CONTACTING A COMPOUND OF THE STRUCTURAL FORMULA RR1ALOR2, WHEREIN R AND R1 EACH COMPRISES ALKYL OF AT MOST 3 CARBON ATOMS AND R2 IS SELECTED FROM THE GROUP CONSISTING OF ALKYL AND CYCLOALKYL, WITH ALUMINUM CHLORIDE, AND RECOVERING FROM THE REACTION MIXTURE A COMPOUND SELECTED FROM THE GROUP CONSISTING OF RR1ALCL, RALCL2 AND R1ALCL2. 